The present invention relates, in general, to an improved surgical biopsy instrument and, more particularly, to a remote thumbwheel mechanism for use in a surgical biopsy instrument.
The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense interest in the medical community. Non-invasive methods for examining tissue and, more particularly, breast tissue include palpation, X-ray imaging, MRI imaging, CT imaging, and ultrasound imaging. When a physician suspects that tissue may contain cancerous cells, a biopsy may be done using either an open procedure or in a percutaneous procedure. In an open procedure, a scalpel is used by the surgeon to create an incision to provide direct viewing and access to the tissue mass of interest. The biopsy may then be done by removal of the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). In a percutaneous biopsy, a needle-like instrument is inserted through a very small incision to access the tissue mass of interest and to obtain a tissue sample for examination and analysis. The advantages of the percutaneous method as compared to the open method are significant: less recovery time for the patient, less pain, less surgical time, lower cost, less disruption of associated tissue and nerves and less disfigurement. Percutaneous methods are generally used in combination with imaging devices such as X-ray and ultrasound to allow the surgeon to locate the tissue mass and accurately position the biopsy instrument.
Generally there are two ways to percutaneously obtain a tissue sample from within the body, aspiration or core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into small enough pieces to be withdrawn in a fluid medium. Application is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core biopsy, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors and no single procedure is ideal for all cases.
A number of core biopsy instruments which may be used in combination with imaging devices are known. Spring powered core biopsy devices are described and illustrated in U.S. Pat. Nos. 4,699,154, 4,944,308, and Re. 34,056. Aspiration devices are described and illustrated in U.S. Pat. Nos. 5,492,130; 5,526,821; 5,429,138 and 5,027,827.
U.S. Pat. No. 5,526,822 describes and illustrates an image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument which takes multiple tissue samples without having to re-puncture the tissue for each sample. The physician uses this biopsy instrument to xe2x80x9cactivelyxe2x80x9d capture (using the vacuum) the tissue prior to severing it from the body. This allows the physician to sample tissues of varying hardness. The instrument described in U.S. Pat. No. 5,526,822 may also be used to collect multiple samples in numerous positions about its longitudinal axis without removing the instrument from the body. A further image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument is described in commonly assigned U.S. Ser. No. 08/825,899, filed on Apr. 2, 1997 and in U.S. Pat. Nos. 6,007,497; 5,649,547; 5,769,086; 5,775,333; and 5,928,164. A handheld image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument is described in U.S. Pat. No. 6,086,544 and in U.S. Pat. No. 6,120,462. The instrument described therein moves drive motors and other electronic components into a control unit separate from and remotely located from the biopsy probe. Biopsy probe cutter rotational and translational motion is transferred from the motors in the control unit to the biopsy probe via flexible coaxial cables. This arrangement improves the cleanability of the reusable hardware that remains in close proximity to the biopsy site as well as improves the life and durability of the electric motors and electronic components now remotely located from the biopsy probe. The biopsy instrument described and illustrated in U.S. Pat. No. 6,086,544 and in U.S. Pat. No. 6,120,462 was designed primarily to be a xe2x80x9chand heldxe2x80x9d instrument to be used by the clinician in conjunction with real time ultrasound imaging. Several imageguided, vacuum-assisted, percutaneous, coring, breast biopsy instruments are currently sold by Ethicon Endo-Surgery, Inc. under the Trademark MAMMOTOME(trademark).
The majority of breast biopsies done today, however, utilize an x-ray machine as the imaging modality. Using x-ray requires that the biopsy instrument be affixed to the x-ray machine by some type of bracket arrangement. Since the biopsy instrument is fixed to a portion of the x-ray machine there is now a need for a means to conveniently rotate the biopsy probe once it is advanced into the breast in order to accurately position the vacuum port at the distal end of the probe.
In U.S. Pat. No. 5,769,086 a biopsy probe is disclosed which includes an electric motor, connected to the proximal end of the biopsy probe via a gear train. Activating the motor causes rotation of the piercing element of the biopsy probe so that multiple tissue specimens may be obtained by the clinician at any location around the center axis of the probe. U.S. Pat. No. 5,649,547 illustrates and describes a biopsy instrument which includes a xe2x80x9cthumb wheelxe2x80x9d at the proximal end of the biopsy probe piercing element. The thumb wheel provides a convenient place for the clinician to grasp the piercing element to manually rotate the biopsy probe about its center axis so that multiple tissue samples could be taken at any position, as determined by the clinician, about the axis of the probe. There are a couple of problems, however, that become evident when this arrangement is put into clinical use. First, when the biopsy probe is used in combination with and mounted to an x-ray machine, it can be difficult for the clinician to get access to the thumb wheel portion of the biopsy probe because of brackets, hoses, and other obstructions in the area around the probe.
It would, therefore, be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, cable driven breast biopsy instrument which may be conveniently mounted to an x-ray machine, and incorporate in it a remotely located means to manually rotate the probe, located in an area away from the surgical site and easily accessible by the clinician. It would further be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, cable driven breast biopsy instrument which may be conveniently mounted to an x-ray machine which would incorporate a port rotation knob located at the proximal end of the biopsy instrument.
The present invention is directed to a biopsy instrument including a base assembly including a firing mechanism movably attached to a distal end of the base assembly, a probe assembly detachably mounted to the base assembly and a drive assembly detachably mounted to the cutter assembly and including a flexible drive shaft operatively connected to the cutter. The probe assembly including a piercer assembly and a cutter assembly detachably affixed to the base assembly. The piercer assembly including a piercer and a probe mount supporting the piercer. The piercer including a distal port, a vacuum lumen, a cutter lumen and a first gear mechanism affixed to a proximal end of the piercer. The cutter assembly includes a cutter adapted to move through the cutter lumen, an adjustment wheel extending from a proximal end of the cutter assembly and a drive rod connected to the adjustment wheel, the drive rod being operatively connected to the first gear mechanism.
The present invention is further directed to a biopsy instrument including a base assembly including a firing mechanism moveably attached to a distal end of the base assembly, a probe assembly moveably attached to the base assembly and a drive assembly detachably mounted to the cutter assembly, the drive assembly including a flexible drive shaft operatively connected to the cutter. The probe assembly including a piercer assembly which includes a piercer moveable from a proximal position to a distal position, a probe mount supporting the piercer and a cutter assembly detachably affixed to the base assembly. The piercer including a distal port, a vacuum port, a cutter lumen and a first gear affixed to a proximal end of the piercer. The probe mount including a second gear affixed to a drive shaft and the second gear meshing with the first gear and a fork coupling detachably mountable to the firing mechanism. The cutter assembly including a cutter adapted to move through the cutter lumen, an adjustment wheel extending from a proximal end of the cutter assembly and a drive rod connected to the adjustment wheel, the drive rod being slideably affixed to a proximal end of the drive shaft such that rotation of the adjustment wheel rotates the piercer as the piercer moves from the proximal position to the distal position.